What Magnets Are Permanent?
Magnets are usually permanent in our minds when we think of them. After all, they stick on our filing cabinets and fridges. But what are these magical magnets really made of? And what makes them so persistent and powerful? This article will explain how to identify a permanent magnet.
Magnets produce their own magnetic fields, which are invisible and attract certain metals. The metals that are attracted to permanent magnets by ferromagnetic materials are known as ferromagnetic. Iron and its alloys as well as nickel, gadolinium and lodestone are all examples. Magnets can stick to other materials as well, such a wood, glass or plastic. When a magnet sticks, it is because the magnetic field lines of the material cross and are attracted together.
The spinning particles or domains in the magnets' interiors are responsible for creating magnetic fields. In most materials their spins, orbits, and other properties are arranged randomly and cancel out each other. This means that they cannot create magnetic fields. In ferromagnetic substances, however, all the nuclear and electron spins align and produce strong magnetic fields. Permanent magnets made of ferromagnetic substances have magnetic fields that are locked by their structure.
The most common permanent magnets include neodymium magnets, Samarium Cobalt magnets, Ceramic Magnets and AlNiCo magnets. The rubber magnets or plastic molded magnets are also permanent magnets which belong to bonded magnet category but virtually they are either ceramic magnet or neodymium magnet powder bonded together with rubber or plastics.
There do have some other types of permanent magnets but they are very rare and not produced and used by volume.
On the contrary, the electromagnet is not permanent magnet. Electromagnets require a constant flow of electricity to maintain their magnetic properties. This is why we need batteries and electricity to power them. When the electricity is cut off, the magnetic field will disappear. So Electromagnet is not permanent magnet.
There are two types of permanent magnets: hard ferromagnetic and soft ferromagnetic. Permanent magnets consist of hard ferromagnetic metals and they retain their magnetic properties, even after demagnetization. They have a high retentivity, and a high force of coercion that resists demagnetization.
These are the strongest magnets available in commercial production today. They are used in motors, refrigerator seal gaskets, and many other applications that need very high magnetic properties.
They are made up of a mixture between iron and other metallic elements that are crystallized on a cubic system. They are brittle but have good corrosion resistance. They can also be cast into complex shapes. They are suitable for high temperature applications and have a good coercive and retentivity force that resists demagnetization.
These are difficult and expensive to manufacture. These are used primarily for very specialized applications. They are made up of a combination of samarium with cobalt. They have a very high retentivity. Samarium-cobalt, the most magnetic material found on Earth, is also a component.